Discovery-driven experiments in undergraduate laboratory courses have been shown to increase student learning and critical thinking abilities. To this end, a lab module involving worm capture by a nematophagous fungus was developed. The goals of this module are to enhance scientific understanding of the regulation of worm capture by soil-dwelling fungi and for students to attain a set of established learning goals, including the ability to develop a testable hypothesis and search for primary literature for data analysis, among others. Students in a ten-week majors lab course completed the lab module and generated novel data as well as data that agrees with the published literature. In addition, learning gains were achieved as seen through a pre-module and post-module test, student self-assessment, class exam, and lab report. Overall, this lab module enables students to become active participants in the scientific method while contributing to the understanding of an ecologically relevant model organism.

Discovery-driven experiments in undergraduate laboratory courses have been shown to increase student learning and critical thinking abilities. To this end, a lab module involving worm capture by a nematophagous fungus was developed. The goals of this module are to enhance scientific understanding of the regulation of worm capture by soil-dwelling fungi and for students to attain a set of established learning goals, including the ability to develop a testable hypothesis and search for primary literature for data analysis, among others. Students in a ten-week majors lab course completed the lab module and generated novel data as well as data that agrees with the published literature. In addition, learning gains were achieved as seen through a pre-module and post-module test, student self-assessment, class exam, and lab report. Overall, this lab module enables students to become active participants in the scientific method while contributing to the understanding of an ecologically relevant model organism.

Overview of lab module and experimental protocol. (A) The class schedule for the lab module. The week 3 experiment involves students attending lab outside of normal class times. (B) An outline of the experimental protocol (full protocol in Appendix 4). Students examine survival of worms on CMA plates with or without A. oligospora. Percent survival (worms on the fungus plate divided by worms on the plate lacking fungus) is compared between control and variable conditions.

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FIGURE 1.

Overview of lab module and experimental protocol. (A) The class schedule for the lab module. The week 3 experiment involves students attending lab outside of normal class times. (B) An outline of the experimental protocol (full protocol in Appendix 4). Students examine survival of worms on CMA plates with or without A. oligospora. Percent survival (worms on the fungus plate divided by worms on the plate lacking fungus) is compared between control and variable conditions.

Class data examining the effects of different variables on A. oligospora-dependent capture of C. elegans. A. oligospora was struck on CMA plates one week prior to the experiment and incubated at room temperature. The experiment was performed as outlined in Figure 1(B) and Appendix 4. At t = 6 h and t = 24 h following worm addition, students rinsed the worms off the CMA plates and calculated percent survival. Data are presented as a ratio of percent survival in the variable condition compared to the control. Data from at least 5 groups for each variable were averaged and the standard error of the mean (SEM) is noted. The pre-treatment worm variable involved the addition of C. elegans to CMA plates 24 hours prior to the start of the experiment. These worms were rinsed off immediately before the experiment began. For the mannose, P. aeruginosa and P. aeruginosa culture media variables, each was added to the CMA plates two hours before the experiment began.

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jmbe/14/2/jmbe-14-230f2.gif

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FIGURE 2.

Class data examining the effects of different variables on A. oligospora-dependent capture of C. elegans. A. oligospora was struck on CMA plates one week prior to the experiment and incubated at room temperature. The experiment was performed as outlined in Figure 1(B) and Appendix 4. At t = 6 h and t = 24 h following worm addition, students rinsed the worms off the CMA plates and calculated percent survival. Data are presented as a ratio of percent survival in the variable condition compared to the control. Data from at least 5 groups for each variable were averaged and the standard error of the mean (SEM) is noted. The pre-treatment worm variable involved the addition of C. elegans to CMA plates 24 hours prior to the start of the experiment. These worms were rinsed off immediately before the experiment began. For the mannose, P. aeruginosa and P. aeruginosa culture media variables, each was added to the CMA plates two hours before the experiment began.

Assessment of learning gains based on a pre-/posttest, class exam and lab report. (A) Student scores from pre-/posttests were analyzed to assess achievement of the lab module learning goals. Class averages on each question along with the SEM (standard error of the mean) are shown. Data were analyzed using Student’s t-test. All questions have a p < 0.0001 when comparing pre- and postmodule scores except Q7 (p < 0.002). (B) Student scores from an exam were analyzed to assess achievement of the lab module learning goals. Class averages for questions relevant to the nematophagous fungi experiment along with the SEM are shown (compared to the overall exam score with and without the module questions). The module questions made up 20% of the total exam by point value. (C) The students wrote a lab report in the format of a scientific paper analyzing their experimental data. Hypotheses were graded according to the following 2-point rubric: 2/2 – A clear and concise hypothesis that is testable with the nematophagous fungi experiment performed in class, 1/2 – A testable hypothesis but not concise or clearly written, 0/2 – No obvious statement of hypothesis. The entire lab report rubric can be found in Appendix 7.

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jmbe/14/2/jmbe-14-230f3.gif

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FIGURE 3.

Assessment of learning gains based on a pre-/posttest, class exam and lab report. (A) Student scores from pre-/posttests were analyzed to assess achievement of the lab module learning goals. Class averages on each question along with the SEM (standard error of the mean) are shown. Data were analyzed using Student’s t-test. All questions have a p < 0.0001 when comparing pre- and postmodule scores except Q7 (p < 0.002). (B) Student scores from an exam were analyzed to assess achievement of the lab module learning goals. Class averages for questions relevant to the nematophagous fungi experiment along with the SEM are shown (compared to the overall exam score with and without the module questions). The module questions made up 20% of the total exam by point value. (C) The students wrote a lab report in the format of a scientific paper analyzing their experimental data. Hypotheses were graded according to the following 2-point rubric: 2/2 – A clear and concise hypothesis that is testable with the nematophagous fungi experiment performed in class, 1/2 – A testable hypothesis but not concise or clearly written, 0/2 – No obvious statement of hypothesis. The entire lab report rubric can be found in Appendix 7.